Modeling biological control of stable flies (Stomoxys calcitrans) by means of Spalangia cameroni

Modeling biological control of stable flies (Stomoxys calcitrans) by means of Spalangia cameroni

Henrik Skovgård¹ and Gösta Nachman²

Stable fly (Stomoxys calcitrans) is a serious pest in dairy cattle production due to their blood-sucking foraging behavior, which is stressful to both humans and cattle. Thus, stable flies affect animal welfare and reduce the amount, quality and quantity of produced milk. Insecticides are usually applied to control this noxious insect, but often with unsatisfactory results. Furthermore, chemical control has a number of unwanted side-effects, including risk of chemical residues in the milk and development of insecticide resistance. Therefore, research efforts should be directed towards finding alternatives.

The parasitoid Spalangia cameroni attacks pupae of stable flies. Field experiments have demonstrated that mass releases of the parasitoid can effectively suppress population density of stable flies in Danish cattle farms. However, almost nothing is known about how this parasitoid can be used optimally so as to minimize the costs associated with biological control. In order to design an optimal control stra­tegy, we have developed a simulation model of the system, allowing us to simulate different control strategies. The model is stage-structured and uses a unified mathematical approach to model daily survival, hatch and fecundity rates as functions of ambient temperature and an insect’s physiological age. Data for the model originate from our own experiments and existing literature. The interactive simulation program allows us to test the combined effects of various control strategies, such as inundative releases of parasitoids, removal of manure, and application of larvacides, on the abundance of stable flies.

 ¹ Section of Entomology and Pathology, Department of Agroecology, University of Aarhus, Denmark (henrik.skovgaard@agrsci.dk)

² Section of Ecology and Evolution, Department of Biology, University of Copenhagen, Denmark (gnachman@bio.ku.dk)